Day 12: Add C solution

12/input.txt

@@ -0,0 +1,20 @@
+VJ-nx
+start-sv
+nx-UL
+FN-nx
+FN-zl
+end-VJ
+sv-hi
+em-VJ
+start-hi
+sv-em
+end-zl
+zl-em
+hi-VJ
+FN-em
+start-VJ
+jx-FN
+zl-sv
+FN-sv
+FN-hi
+nx-end

12/solution.c

@@ -0,0 +1,40 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+
+                                 struct{
+                               #define K(a\
+                              ,b) ((a&0x3f)\
+                              <<6|(b&0x3f))
+                               int n,e[8];}
+                            G    [K('z',
+                           'z'             )]={
+                         0} ;              int p[
+                       64]={                  0},l=
+                     0;int      R(int           l,int
+                   D){        int C=0,            c=p[l
+                 -1],N             ,d,              i=0,j
+              ;if(c               ==1)                return
+               1;                 for(                  ;i
+    <G[c].n;                    i++){N=                     G[c].e[i
+  ];d=0;if(N){             if((N&0x800)){for              (j=0;j<l;j++
+ )if(p[j]==N){d          =1;break;}}if(!d||D){p          [l]=N;C+=R(l+1
+ ,d ? 0:D);}}}         return     C;}     int k(          char*s){return
+  (!strcmp(s,""        "star"     "t"      ))?0:(         !strcmp(s,"e"
+    "nd"))?1            :K(s[0]/* I HATE */,s[1])            ;}int
+             main         ()/* GRAPH THEORY */{         char
+              a[8]         ,b[8];while(scanf         ("%7"
+                "[^-]"                             "-%7"
+                  "s\n"                          ,a,b)
+                    ==2){                      int A
+                      =k(a)                   ,B=k
+                        (b);G               [A].
+                          e[G[A           ].n++
+                            ]=B;           G[
+                                 B].e[G[B
+                               ]. n++]=A;}
+                              printf("Silver"
+                              ": %d Gold: %d"
+                               "\n",R(1,0),
+                                 R(1,1));}